HD6433832S Datasheet, PDF (267/560 Pages) Renesas Technology Corp – single-chip microcomputers

Transmit Data Register (TDR)
Bit
Initial value
Read/Write
7
TDR7
1
R/W
6
TDR6
1
R/W
5
TDR5
1
R/W
4
TDR4
1
R/W
3
TDR3
1
R/W
2
TDR2
1
R/W
1
TDR1
1
R/W
0
TDR0
1
R/W
The transmit data register (TDR) is an 8-bit register for holding transmit data.
When SCI3 detects that the transmit shift register (TSR) is empty, it shifts transmit data written in
TDR to TSR and starts serial data transmission. While TSR is transmitting serial data, the next
byte to be transmitted can be written to TDR, realizing continuous transmission.
TDR can be read or written by the CPU at all times.
TDR is initialized to H'FF upon reset or in standby mode, watch mode, subactive mode, or
subsleep mode.
Serial Mode Register (SMR)
Bit
7
6
5
4
3
2
1
0
COM CHR
PE
PM STOP MP CKS1 CKS0
Initial value
0
0
0
0
0
0
0
0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
The serial mode register (SMR) is an 8-bit register for setting the serial data communication
format and for selecting the clock source of the baud rate generator. SMR can be read and written
by the CPU at any time.
SMR is initialized to H'00 upon reset or in standby mode, watch mode, subactive mode, or
subsleep mode.
Bit 7—Communication Mode (COM): Bit 7 selects asynchronous mode or synchronous mode as
the serial data communication mode.
Bit 7: COM
0
1
Description
Asynchronous mode
Synchronous mode
(initial value)
252